Today's forecast and storm roundup

The heat and chances of thunderstorms continue Sunday with highs in the mid-90s and a 20 percent chance of isolated rain and thunderstorms, according to the National Weather Service. It is supposed to remain in the 90s all week with heat index values in the low to mid-90s on Monday and Tuesday.

The temperature at BWI at 1 p.m. Sunday was 96 with heat index making it feel like 101. On Calvert Street it was 97 with 52 percent humidity.

In a statement issued at noon, the National Weather Service said they expect maximum heat index values to range from 100-102. Baltimore city's health department said Sunday afternoon that it has extended the Code Red Heat Alert through Tuesday, meaning cooling centers will be open and distributing water.

Friday's storm system, which was blamed for at least 2 deaths in Maryland, is called a derecho. On its Facebook page, The National Weather Service defines derecho as "a long-lived damaging wind storm associated with a band of rapidly moving thunderstorms." The central Maryland/Northern Virginia area averages 1 derecho every 2 or 3 years, the National Weather Service said, and the last one here was June 4, 2008. More on derechos from the National Weather Service can be found here.

Downed trees can still be found throughout the area, and readers are uploading their images here.

Turn off or unplug sensitive electronic equipment and appliances to avoid damage from surges when power return.

Do not use candles as lighting.

Leave one light turned on so you'll know when the power is restored.

Connect the equipment you want to power directly to the outlets on a portable generator. Do not connect a portable generator to a home's electrical system.

Never use a generator, grill or other gasoline, propane, natural gas or charcoal-burning devices inside a home or any partially enclosed area. Locate unit away from doors, windows and vents that could allow carbon monoxide to come indoors.<P>

Avoid fallen or low-hanging wires or anything they contact. Be especially cautious near metal fences.

Be mindful of food spoilage. Food safety tips from the city's health department can be found here.